Swivel table alignment



Feb. 5 H95? B. H. GOEHRING 29780,94@ v SWIVEL TABLE ALIGNMENT Filed Aug.17, 1955 2 sheets-sheet 1 m mulnuu INVENTOR 56m/A RD H. Gogh/mm@ Feb. 5,1957 B. H. GOEHRING SWIVEL TABLE ALIGNMENT 2 Sheets-Sheet 2 Filed Aug.17, 1955 A T TGR/VE Y Unite States Patent G SWIVEL TABLE ALHGNMENTBernhard H. Goehring, Worcester,

ton Company, Worcester, sachusetts Application August 17, 1955, SerialNo. 528,927 6 Claims. (Cl. 51-240) Mass., assigner to Nor- Mass., acorporation of Mas- One object of the invention is to provide a simpleand thoroughly practical swivel adjusting mechanism for a machine tooltable. Another object ofthe invention is to provide apparatus forprecisely indicating the extent of angular adjustment of a swivel table.Another object is to provide a control indicator arranged to give aprecise indication of taper in terms of taper as in thousandths orfractions of thousandths of an inch per inch or per foot. Ano-therobject is to provide apparatus at one end of the Swivel table for givingan indication of taper. Another object is to provide apparatus at theother end of 'the swivel table for giving an indication of deection ofthe swivel table. Another object is to provide means to adjust theswivel table to facilitate compensating for deilection. Another objectis to provide a single indicating meter having duplicate indicatingneedles, one to indicate taper, and the other to indicate deflection.Other objects will be in part obvious or in part pointed outhereinafter.

In the accompanying drawings, in which is shown one of various possibleembodiments of the mechanical features of the invention in which;

Fig. l is a plan view of a grinding machine work table and a swiveltable embodying the invention,

Fig. 2 is a fragmentary right hand end elevation, on an enlarged scale,of the work and swivel tables showing the swivel indicating apparatus;

Fig. 3 is a fragmentary left hand end elevation, on an enlarged scale,of the work and swivel tables showing the deflection indicatingapparatus;

Fig. 4 is a fragmentary vertical sectional View, on an enlarged scale,taken approximately on the line 4-4 of Fig. l, through the right handend pick-up unit and associated parts;

Fig. 5 is a vertical sectional view, taken approximately on the line 55of Fig. 4, through the linear variable differential transformers andassociated parts; j t

Fig. 6 is a vertical sectional View, on an enlarged scale, takenapproximately on the line 6--6 of Fig. 3, through the linear variabledifferential transformers of the left hand end pick-up unit;

Fig. 7 is an electric diagram;

Fig. 8 is a front elevation of a meter;

Fig. 9 is a vertical sectional view through the meter as shown in Fig.8; and

Fig. l0 is a fragmentary vertical sectional view, taken approximately onthe line lill0 of Fig. 3, showing the means for rendering the deflectionadjusting mechanism operative or inoperative.

A portion of a machine tool has been illustrated in the drawings,comprising a longitudinally movable table 10 which supports a swiveltable 11. The swivel table 11 serves as a work support which may includea well known chuck or a pair of spaced work supporting centers (notshown) for rotatably supporting a Work piece to be ground. The swiveltable 11 is arranged toswivel in a horizontal plane about a verticallyarranged pivot stud 12 2,780,040 Patented Feb. 5, 1957 carried by ythetable 10. The opposite: ends of the swivel table 11 are provided withprojecting ends 20 and 21. A pair of clamp and guide blocks 22 and 23are provided on the table lil to facilitate clamping the projecting ends20 and 2l to the table 10 after the swivel table 11 has been swivelledto the desired extent. The clamping blocks 22 and 23 may be tightened toclamp the swivel table il in adjusted position relative to the table 10.lf desired, however, the clamping blocks 22 and 23 may be partiallytightened so as to provide sufficient friction nor mally to hold theswivel table l1 in adjusted position, in which condition the swiveltable 1l may be swivelled without releasing the clamping blocks 22 and23.

A swivelling mechanism is provided comprising a rotaable screw l5carried bythe swivel table 11 which meshes with or engages a nut 16mounted on the table 10. The nut 16 is free to rotate and to slidelongitudinally relative to the table l0 during a swivel adjustment ofthe swivel table 11. The screw 15 is rotatably journalled in a bearing17 which is fixedly mounted on the swivel table 11. The left hand end ofthe screw i5 (Fig. 2) is provided with an enlarged head having a formedaperture 18 by means of which the screw may be rotated by means of amanually operable wrench.

in order to facilitate swiveling the table to a predetermined angle theclamping block 2? is provided on its upper surface with anarcuate-shaped graduated scale 24. The graduations of the scale 24 mayread or indicate taper in inches per foot. The above describedswivelling mechanism serves to facilitate a preliminary swivel settingof the swivel table 1l. After the preliminary setting has been made, awork piece may then be ground after which the taper is measured by amicrometer caliper to determine the extent of error, if any, in thepreliminary setting. ln order to make a precise adjustment necessary tosecure the desired and predetermined taper, a sensitive indicatingapparatus to be hereinafter described may be utilized.

The swivel adjusting screw 15 and associated nut 16 are mounted at theright hand end of the swivel table 11 which in a cylindrical grindingmachine supports a footstock (not shown). ln such a machine theheadstock which is a relatively heavy part is usually supported on theleft hand end of the swivel table 11.. When a swivel adjustment is made,due to the weight on the table, the table may be slightly deflected dueto the heavy weight on the left hand end thereof causing additionalfriction between the swivel table 1l and the longitudinally movabletable 10.

It is desirable to provide an indicator to show just how much deflectionhas taken place when the table 11 is swivelled. This is preferablyaccomplished by provision of a longitudinally extending cylindricalclearance bore or hole 25 in the swivel table ll. A deection rod 26passes through the clearance hole 25. The right hand end of the deectionrod 25 tits within a hole 27 (Fig. l) within the swivel table 1li and isfastened therein by means of a pair of spaced set screws 28 and 29. Theleft hand end of the deflection rod 26 projects beyond the left hand endof the swivel table 1l and rests upon a horizontally arranged knife-edgeor a plane surface 30 formed on a bracket 3l (Fig. 3) fastened on theleft hand end of the swivel table 1l. The bracket 3l serves to supportthe left hand end of the deflection rod 2d and is arranged to allow thedeflection rod to slide thereon in case the table is deflected duringswivel adjustment thereof. In order to determine the extent ofdeflection in the swivel table 11, a pick-up unit 35 is adjustablyfastened to the left hand end of the swivel table li. A slide rod 37 ofthe pick-up unit 35 is fastened to the left hand end of the deflectionrod 26. Any deflection of the swivel table l1 during a swivel adjustmentcauses a relative motion between the lefthand end of swivel table l1 andthe left asados() n.9 hand end of the deflection rod Zo which impartsaxial movement to the slide rod 17 of the pick-up unit 35.

A pick-up unit 36 is adjustably mounted on the right hand end of thelongitudinally movable table it?. A bracket 38 is fastened to the righthand end of the swivel table il and serves as a support for an adjustingscrew 39 which is anranged in axial alignment with an actuating plungerall of the pick-up unit 36.

The actuating plunger d@ (Fig. of the pick-up unit 36 is connected tothe left hand end of a rod f-i of a nonferrous metal. The other end ofthe rod ii is secured to a ferrous metal core 42. A rod 43 ofnon-.ferrous metal is connected to the right hand end of the core d2. Aiiat spring 4d supports the 'rods dii-fili and a fiat spring #i5supports the right hand end of the rod 43. It will be readily apparentfrom the foregoing disclosure that actuation of the `screw .'59 servesto move the rods dii-di-AS in an axial direction to impart an axialadjustment to the core ft2. The upper part of `the pick-up unit 365 isprovided with a cylindrical aperture 46 which is arranged to support aplurality of coils 47, d@ and 49 of a linear variable differentialtransformer. A sleeve Si? is screw threaded into the right hand end ofthe aperture d6 and serves to hold the coils 47, #i8 and 49 in position.The linear variable differential transformer will be hereinafterreferred to as L. V. D. T. it will be now seen that the L. V. D. T.iL-fJ-d-w is operated whenever the screw 39 engages and moves the rodit) in an axial direction and that the springs fili and 45 provide arestoring force normally to maintain the core 42 in a central positionwhen the screw 39 is out of engagement with the rod dit.

There is a second L. V. D. T. in the pick-up unit 36 comprising a coreand three coils 56, 57 and 58. The coils 56, 57 and Se are supported bya sleeve 5S which fits within a cylindrical aperture 59. The core 54 ismounted on the left hand end -of an adjusting screw 62 (Fig. 5), bymeans of which the core may be adjusted in an axial direction. A setscrew 63 is provided to facilitate locating the screw 62 in adjustedposition. The function of the L. V. D. T. S4-S6-5'7-55, which isconnected electrically in opposition to L. V. D. T. 42-47-48-49 as willbe more fully described hereinafter, is to stabilize the zero outputpoint of the pick-up unit 36. Practical L. V. D. T.s exhibit a iinitynon zero null voltage due to slight manufacturing inaccuracies in thewind of the coils, mechanical asymmetry of the core pie-ce and windingformation, imperfect alignment of core and coils, etc. Temperaturechanges affect the physical dimensions of the core piece, its magneticpermeability and conductivity, and the resistance and inductance of thecoil windings, which is in any lor all of which may affect the magnitudeof the null voltage and the position of the core at which it occurs.Similarly, changes in the excitation voltage applied to the primarywinding, as described below, effects the operating point of theinduction curve of the core piece, heating of the coils, harmonicgeneration, etc. These residual effects are significant in L. V. D. T.sbecause the output voltage is the difference between induced E. M. Fisin two secondary coils, said difference being a small fraction of theinduced E. M. F. To achieve the most stable operation, a second L. V. D.T. 54l-56- 57-5, preferably having characteristics matching that of thefirst L. V. D. T. i2- d'7 @iS-49, is mounted in physical proximity to,and excited from the same -source as-the first, with its outputconnected substractively in series with that of the rst L. V. D. T. toeffect a reduction in the new output aero drift arising from thosecauses which affect both L. V. D. T.s equally.

Changes in the exciting voltage applied to the primary winding canchange the zero or null position and as the operator sets the meterneedles to Zero position this might, at first blush, seem to be of noconsquence. However, if between the time the operator sets the needlesto the Zero position and the time he turns the swivel adjusting screw tocorrect adjustment, there is a change in the excitfiiing voltage, it canproduce an error were it not for the second L. V. D. T. lt is well knownthat voltages on power lines can iiuctuate within considerable limitsdependent upon the load upon the line and at any second the closing of aswitch somewhere in the system to double the load on the line mightoccur, changing the exciting voltage. Furthermore, if there were nosecond L. V. D. T. to counterbalance such changes the operator, seeingthe needles of the meter move during the course of a machining operationmight take a good many minutes, might conclude that the clamping screwsfor holding the swivel table 11 to the table iii and which arepreferably provided to keep loads off the nut and screw adjustingmechanism, had slipped. With the second L. V. D. T. in accordance withthe preferred embodiment of this invention the operator can watch theneedles of the meter to be sure that the clamping screws have notslipped.

On the other hand, for applications where the sensitive requirements areless stringent, inherent drift of the first L. V. D. T. may have only atrivial inliuence on indications of a meter. in which case 'the second,compensating L. V. D. T. may be omitted. it is assumed in the 'balanceof this description that wherever the second L. V. D. T. is included itis only by way of illustration and it may, for many practicalembodiments be left out of the apparatus.

The pick-up unit 35 is preferably adjustably mounted on the left handend of the swivel table lli and serves to give an indication ot' thedeflection of the table during a Iswivel `adjustment thereof. Thepick-up unit 35 is provided with an L. V. D. T. comprising a core gliand a plurality of coils Sli, 82 and g3 (Fig. 6). The coils aresupported in a cylindrical bore tid and are held in position by a plugS5 threaded into a threaded aperture in the pick-up unit 35. The coredi) is mounted on the left hand end portion 8o of a rod 37. The righthand end of the rod 37 is fixedly connected to the left hand end of thedeflection rod 26 (Fig. l). it will be readily apparent that during aswivel adjustment of the table 11, any deflection of the table ii. willproduce a relative motion of the core 80 relative to the coils 8l, d2and 33.

The pick-up unit 35 (Fig. 6) is provided with a second L. V. D. T.comprising a core 9i. and a plurality of coils 92, 93 and 94. The coils92, 93 and 9d fit within a sleeve 95 which in turn fits within acylindrical bore 96 formed within the unit 35. The coils 92, 93 and 94are held in position by means of a sleeve 97 which ts within the bore 96and is held in position therein by a set screw 98. The core 9i isfastened to the right hand end of an adjusting screw 99. A set screwiii@ is provided to facilitate locking the adjusting screw 99 inadjusted position. The function of the L. V. D. T. 9ll-92-93-94, whichis connected electrically in opposition to the L. V. D. T. -81-82-83 aswill be more fully described hereinafter, is to stabilize the zerooutput point of the pick-up unit 35.

The L. V. D. T.s of the pick-up units 35 and 36 are connected to theelectronic mechanism by cables '70 and 71, as indicated in Fig. l. Fig.4 illustrates the mechanical features of the cable connection where thecable 71 is located in an insulating bushing 72 held in place by meansof a threaded sleeve *73 screwed into a boss 74 on the end wall of thepick-up unit 3o. it is believed that the foregoing description togetherwith the drawings amply explains the mechanical features of theactuating L. V. D. T.s and the associated parts which mechanicalfeatures can be widely varied, and I will now describe the electricaland electronic features of Fig. 7 including also the meter of Figs. 8and 9. Where non-ferrous parts Were mentioned other low permeablematerial could be used and ferrous is to be deemed to mean any materialsatisfactorily permeable.

In Fig. 7, the L. V. D. T. 42-47-48-49 and the L. V. D. T.54--56--57--58, whose secondary windings 47-49 and 56-58 aresubir-actively connected as hereinbefore explained, provide the signalinput to A. C. amplifier 101, said signal voltage being proportional tothe excitation current supplied to primary windings 48 and 57 fromoscillator 105 and to the displacement relative to its null position ofcore 42. The output signal from A. C. :amplifier 101 is the signal inputto phase sensitive detector 103, a phase reference carrier voltage beingsupplied to phase sensitive detector 103 from oscillator 105. Theloutput voltage of phase sensitive `detector 103 is linearlyproportional to the component of the input signal to A. C. .amplifier101 in phase with Athe reference voltage applied vto phase sensitivedetector 103. Said output voltage is connected to an indicating meter110, and more specifically to terminals 111 `and 112 as shown in Fig. 9,these terminals being internally connected to the moving coil 113 of aDArsonval direct current meter whose indicating pointer is 114.

The amplification or gain of A. C. amplifier 101 is adjusted to asuitable value so that movement of needle 11d from center scale to fullscale represents a useful range of taper adjustment, such as .010l perfoot.

When core 52 moves in one direction from its null position the phasepolarity of the output signal from the assembly of L. V. I). T.42--47-4849 and L. V. D. T. 541-56-57-55 is 180 shifted relative to thephase polarity of said output signal when the displacement of core 42 isin the opposite direction relative to its nuli position. Phase sensitivedetector 103 responds to this phase reversal by reversal of the polarityof its output voltage; consequently needle 11d moves up-scale for onedirection of motion of core 42, and down-scale for the other. Theparticular direction of motion of needle 114 with respect to a givendirection of motion of core 42 may be reversed by interchange of anypair of conductors, for example the signal input leads to A. C.amplifier 101, the signal input leads to phase Isensitive detector 103,the output leads from phase sensitive detector 103 to meter 110, theleads from oscillator 105 to phase sensitive detector 103, or theexcitation leads from oscillator NPS to the assembly comprising L. V. D.T. 42-47-413--49 and L. V. D. T. 5.41-56-57-58. Thus needle 114 re-:sponds to relative motion between table and swivel table 11 asmanifested by movement of screw 39 relative .to pick-up unit 36 at theright hand end of Fig. 1.

In like manner a similar pick-up unit assembly 3S, shown 'at the lefthand end of Fig. 1 is connected, vas shown in Fig. 7, in a circuitcomprising L. V. D. T. 80--81 82li3 :and L. V. D. T. 91-92--93-94, A. C.amplifier 102, phase sensitive detector 104, meter terminals 115 and116, -coil 117 (Figs. 8 and 9), and ultimately to needle 118 of meter110, needle 118 being responsive to the relative displacement of thecore 30 from its null position in exactly the same manner as needle 114is responsive to the relative displacement of core 42 from its nullposition.

Referring to Figs. l and 7, it may be seen that as table 11 swivelsabout its pivot stud 12 in a counter-clockwise direction, core 42 ofpick-up unit 36 is moved inwardly relative to unit 36, while core 80 ofpick-up unit 35 moves at the same time outwardly relative to unit 35.However, needles 11d and 118 are caused to move in the same directionrelative to the scale of meter 110 by a simple interchange of leads asdescribed above. The movement of the core 80 caused by deflection of theleft hand end of swivel table 11 relative to the deflection-rod 2ocauses movement of the needle 113 to give an indication of the extent ofdeflection of the table 11 due to the swivel adjustment.

Power supply 106 furnishes the necessary low voltage A. C. and highvoltage D. C. potentials required for operation of the various amplierdetector and oscillator circuits. The connections between the L. V. D.T.s and the amplifiers, the connections between the amplifier and thephase sensitive detectors, the connections between the ,latter and theseparate instrumentalities of the meter, as

' well as the connections between the oscillator to the phase A. C.single lines in the diagram represent as many wiresY as are necessary toachieve this purpose all as well known in the art.

The pick-up unit 35 is preferably adjustably mounted on the table 10.The clamping block 23 is provided with upwardly extending arcuateslideway 120 which mates with a correspondingly shaped guideway formedon the underside `of the unit 36. A pair .of clamping screws 121 (Fig.2) is provided on unit 36 to facilitate clamping unit 36 in adjustedposition on 4the slideway 120. By adjustment of pick-up unit 36 relative.to slideway 120, or by adjustment of screw 39, ythe needle 114 of themeter 110 may be `read-ily set at Zero in setting up of the machine.

The pick-up unit 35 is adjustably mounted on .the left hand end of the.swivel table 11. The unit 35 may be provided with a horizontallyprojecting lug 125 having an elongated slot 126. A clamping screw 127passes through vthe slot 126 .and is screw threaded into ithe left handend of the swivel table 11. By adjustment of pick-up unit 35transversely relative to the swivel table 11, or by adjusting the screw99, the needle 113 may be readily set at zero in .setting up of themachine.

in the mechanism above described, the needle 114 gives an indication ofthe taper setting of the swivel table 11, and the needle 118 gives anindication. of the extent of deflection or bending `of the swivel table`during the swivel adjustment.

It is desirable to provide a suitable mechanism adjacent to the lefthand end of the table to facilitate compensating for deflection of thetable. This mechanism comprises a rotatable adjusting screw 130 which isrotatably supported by a bracket 131 fastened to the front edge of thetable 10. A reduced cylindrical portion 132 of the screw 139 passes:through an elongated slot 133 formed in a boss 134 projecting from theleft hand end of the swivel table 11. The left hand end of the screw 130adjacent to the portion 132 is formed as a partial spherical thrustsurface 135'. A collar 136, having a pantial spherical thrust surface137 .is mounted on .the portion 132 of the screw 13G. The partialspherical thrust sunfaces 135 and 137 are arranged to engage oppositeside faces of the boss 134 when the adjusting screw 130 is rotated.

The deflection adjusting screw 13d is preferably nor mally inoperativeso that it does not interfere with the swivel adjustment of `the table11. This is preferably accomplished by provision -of a normallydisengaged nut which is operatively engaged with the screw 130 only whenit is desired to make a deflection compensating adjustment. kAsillustrated in Fig. l0, the bracket 131 supports a slidably keyedplunger 138, the right hand end of which is threaded and serves as a nut139 when moved toward the right into engagement with the screw 130. Theplunger 133 is normally held in a left hand end or inoperative positionby means of a compressi-on spring 140. A rotatable sleeve 1111 having aknurled actuating knob 142 is rotatably supported on the plunger 138.The bracket 131 is provided with a pin 143 which rides in a bayonet lockslot 144. It will be readily apparent fnom the foregoing disclosure thatmanual movement of knob 142 toward the right (Fig. l0) against thecompression of spring 140 serves vto move the nut 1139 into operativeengagement with the screw 130. The knob 142 may be held manually in aright hand end position (Fig. 10) to maintain the nut 139 in operativeengagement with the deiieotiou adjusting screw 130 during manualadjustment of the screw 13G, or if desired may be locked in position byturning of the knob 142 in a counter-clockwise direction (Fig. 3). Whennut 139 is in engagement with screw 130, the screw 130 may be rotated ineither arenoso direction to adjust the left hand end of the -swivel:table 1l until the needle 118 reads zero so as tto compensate fordeliection. After this adjustment has been made7 the knob M2 may bereleased or rotated in a clockwise direction so that the releasedcompression of the spring lati moves plunger toward the left (Fig. l0)to disengage nut t3; from the screw tl.

The operation of the swivel table alignment mechanism will be readilyapparent from the foregoing disclosure. rthe clamping blocks Z2 and 23are tightened sufeiently to frictionaliy hold `the swivel table it inadjusted position relative to the table it). The swivel adjusting screwl5 is rotated manually to impart a swivelling movement of the table ilto prete-terminent angie by means of the graduated scale 25.-. A workpiece is mounted on the table l?. and a preliminary grinding operationis performed thereon. The work piece is then measured by micrometer orother gauging means to determine whether table il is swivelled toproduce the desired preetermined taper.

it an additional swivel adjustment is required7 the pick-up unit 3o isadjusted by manipulation of the screw 39 to Zero the needle on the scaleil@ oi the meter titl. The swivel 4adjusting screw l5 is then rotated toimpar-t a further swivel adiustment to the table il. This adjustment ofscrew l5 is continued until the needle itl/fmoves to the desiredgraduation on the scale il@ .of the meter litt. The needle ll of meterliti is then checked. Unless needle H8 reads zero, it lindicates thatthe swivel table ill has been `deilccted during the swivel adjustment.To compensate vfor deiieetion, the knob M2 is moved toward the right(Fig. l0) against the compression of the spring le@ to engage the nut139 with the adjusting screw tt. The screw i3d may then be rotated ineither direction to eliminate deflection `in 4the table il. This latteradjustment is continued until the needle MS reads Zero therebyeliminating detlection. The knob 3144i is lthen released so thatreleased compression of the `spring 14d moves the plunger 138 toward theleft (Fig. l0) to disengage the nut 139 from the screw i3d therebyrendering the deflection adjusting screw i3d inoperative.

It may be necessary to malte one or more swivel compensating adjustmentsoi the swivel table il in 4order to obtain a predetermined taper on theworl; piece. After each swivel adjustment, the meter lill@ must becheek-ed for deection,

It will thus be seen that there has been provided by this inventionapparatus in which the various objects hereinabove set forth togetherwith many thoroughly practical advantages are successfully achieved. Asmany possible embodiments may be made of the above invention and as manychanges might be made in the embodiment above set forth, it is to beunderstood that al1 matter hereinabove set forth or shown in theaccompanying drawings is to be interpreted as illustrative and not in alimiting sense.

l claim:

l. in a machine tool having a longitudinally movable table, a swiveltable pivotally supported thereon, means including a nut and screwmechanism operatively connected between one end of the swivel table andthe longitudinally movable table to facilitate a swivclling adjustmentor" the swivel table, and a dcllection indicating mechanism thereforcomprising a dellection bar, means to lixedly support one end ot saidbar at one end of said swivel table, a dtilection indicating mechanisminterposed between the other end of the swivel table and the deilectionbar, and a meter operatively connected to said mechanism visibly toindicate the extent of dc'l'lection of the swivel table.

2. ln a machine tool, as claimed in claim l, in combination with theparts and features therein specified of a normally inoperative nut andscrew mechanism operatively conncctcd between the other end of theswivel table and the longitudinally movable table adjacent to thedentction indicating mechanism, and manually operable means to rendersalti nut and screw mechanism operative to facilitate adjustment of theswivel table to compensate for dellection.

3. in a machine tool, as claimed in claim l, in comticn n the parts andfeatures therein specified in which the dellection indicating mechanismis mounted on the other end of the swivel table7 operative connectionsbetween said mechanism and said deiiection bar, and means to adjust saidmechanism transversely relative to the swivel ta 1c to facilitateZeroing the needle of said meter .in setti g-up the machine.

4. in a mac .ine tool, as claimed in claim l, in combination with theparts and features therein specified in which one end ot the deflectionbar is Xedly mounted adjacent to one end of the swivel table, theremainder of the bar being arranged so that the swivel table may bedeileeted without moving the other end of said bar, a de- .tlectionindicating mechanism adjnstably mounted on the other end i the swiveltable adjacent to the free end ot the dellection bar, said deflectionindicating mechanism having a movable plunger operatively connected tothe ltree end of the delico-tion bar which is arranged so thatdeflection ot the table produced during a swivelling adjustment causesrelative motion between the end of the swivel table and the tree end ctthe deflection bar, and operative connections between said movableplunger and the meter visibly to indicate tie extent ot the dcliectlonof thc swivel table.

5 a machine tool having a longitudinally movable table, a swivel tablepivotally supported thereon, means including a nut and screw mechanismoperatively connecte-:l between one end of the swivel table and thelongitudinally movable table, means including a nut and screw mechanismto swivel said swivel. table and a taper control indicator mechanismoperatively connected between one end oi tne swivel and thelongitudinally movable table to facilitate a precise angular adjustmentof the swivel table. meter having a pair ot independent movable needles,one of said needles being responsive to said mechanism visibly toindicate the extent or" swivel, a deilection bar having one end lxed tothe swivel table adjacent to the nut and screw mechanism7 a deflectionindicator mechanism interposed between the other end ot the swivel tableand the other end ol` said deflection bar, and operative connectionsbetween said latter mechanism and a second movable needle in said metervisibly to indicate the extent of deiiection of said swivel table due tothe swivelling adjustment.

6. 'in a machine tool, as claimed. in claim 5, in combination with theparts and features therein specified oi means including a normallyinoperative nut and screw mechanism operatively connected between theswivel table and the longitudinally movable table adjacent to thedeflection indicator mechanism, and manually operable means to engagesaid nut with said screw to render said nut and screw mechanismoperative to Yfacilitate imparting a transverse adjustment to the end ofthe swivel table to compensate for deflection.

References Site-: in the ille of this patent UNliTED STATES PATENTS2.600,55() Levesque June i7, 1952

